This message selects a string in a multiple-selection list box.
wParam
Specifies how to set the selection. If the wParam parameter is nonzero, the string is selected and highlighted; if wParam is zero, the highlight is removed and the string is no longer selected.
lParam
The low-order word of the lParam parameter is an index that specifies which string to set. If lParam is -1, the selection is added to or removed from all strings, depending on the value of wParam.
The return value is LB_ERR if an error occurs.
This message should be used only with multiple-selection list boxes.